Stop mechanism



Dec. 31, 1940. *l 1-EAR, 2,227,114

STOP MECHANISM Filed Feb. l0, 1940 A TTORNEY.

Patented Dec. 31,1940

'rar

eroi MncnaNrsr/i y .lames D. Tear, .l Great Neck, N. Y., assignerto Ford rInstrument Company, Inc., Longfsland City, N. Y., a corporation "of New `York p Application February 10, 1940, Serial No. 318,233

p v 11 Claims.

, This invention relates to stop mechanisms and particularly to stop mechanisms for two cooperating componentf'slides the movements of which are' combined to produce a vector movement.

s The principal objectoftheinvfention is to provide a stop'mechan'ism,suchthat the boundary of the area covered by the combined reproduced motion of two component slides will approach a circle instead of a square,` as 'would be the case were lo' simple stops only usedon each slide. y

` Other objects will be apparent from'the specificationA and thedrawing. I i c `In i certain mechanismsl in which movements along rectangular Vcoordinates'rare transmitted to other mechanisms., it is` Giften desirable to limit the movements along thecoordinats such that when they are combined the length of the resulting vector does not exceeda predetermined value.

This 4rediiirement ariseswhenever the mechanical 'movement of the mechanism respondinglto the vector movement must not for mechanical reasons exceed a certain value. For examplein a Plotting apparatus, such ias is fsh'ownin Patent No, 1,753,781, rectangular components are combined to Aproduce a vectordand it `is'desired that the lengthof the vector does `not exceed a value representing the Afull travel of theA individual component slides. When this condition is met, `the combined movements `of the component slides are limited to a eld approachingha circle whose diameter is equal to the fulltravel of the individual slides. in the disclosure made herein, which is different from that in Patent No. 1,753,781,r the held of travel of `the combined movements t of the components is an octagon which suciently approaches a circle for many USBS. y .l

An Aelrlloodirnentof this invention is shown in the accompanying drawing in Whchr f Fig. 1 is a diagrammaticplanI View of* an arrangement to combine components into a vector using differentials. and Y t t Fig. 2 is an elevational View of a similar arrangement using interrneshing gears.V r t Referring particularly to Fig, 1, Ma: andMy represent power units` whose vmotions are inproportion to components of a` movementk (not shown)v resolved along twoaxes X and Y at right anglestoeach.`

Power unitM is connected to shaft I .which has athreaded section 2 and jconventionalstops 3, 3. Threaded on section 2 of shaft Itis Slidell in the form of a nut with conventional stops 5, 5,

positioned tocooperate with stops 3, 3. The slide (Ci. 19a-141) i i il is kept from rotating upon-the movement of shaft 4I by rod 6, mounted on some solid partof theapparatus (not shown) and passing through hole 'l of slide '4. Similarly, rpower unit My is connected to shaft 8, having a threaded p ortion 5 9, on which are mounted stops Ill, I0, andsli'de I I with its cooperating stops I2, I2. Rod I3 secured to the 'frame ofthe apparatus and passing through holelll of slide `I I keeps it from rotating upon movement of'shait 3, but permits it to slide 10 laterally.` l f .l

Shafts land 8 'are connected together subtractively by diierential I5, the output VVof which is shaftI'iS.. On shaft` I5 is a threaded portion I'I, with stops! 8,l lgxa'dapted to cooperate with stops 15 I9, I 9 on slide 'ilwhich is threaded on the portion I I or-,shaft la Slide` 2i! is kept from rotating shaft 'I6 by rod ZI secured to the frame of the apparatus and passing through hole 22 of slide 205. 'I t Similarly ,'`shaft tand shaft 8 are connected to- `gameraacitivreiy'by dicelnuai 2s, the dut-put of which is'shaft 24. On shaft ,24 is a threaded portionijwith `stops 26, 26, adapted to cooperate ywithfstops 21,21 on' slide 28 which is threaded on thep'ortion25 otf'shvait 2li. Slide 28 iskept from rotating' with rshaft4 25 by rod 28, secured to the frame of the'apparatus and passing through hole tllfof slide'Z. u t 'i 'lihe' stops 3, 3 and It, It are'adapted to engage l Y`stops`j5 5 'and' |22- l2 respectively upon the movementlofnshaits vI Vand to the limits of their travel.; qFor purpose of illustration thisis taken as tenjuhits in either direction from their `mean positionajthat is, the limits of the X and Y components areeach il() units. In the assembly of 'the'apparatus slides 4 and Il are located in the `rniddlepffthreadedportions L2 and 9 of shafts I f and Bfrespectivelm: when` shafts l and 3 are Vin the; meanpositions. r y' 1 40 Th 25,25 areadaptedtofentops le; s and 'jg'aeestopsv I9`, Ifand 21;'"2'1 resp'ctivelyupon the movement of shafts I5 and 24 `of J14.14 units of rotation iromtheir 'meanfpositions In vthe as- ,f sernbly 4of vthe apparatus, slides 2i) and 23 are'located inthe middle of threaded portions lIl and 25 of shafts I6 andd respectively when shafts I6" andearein their mean'positions.

t VThe ine :iia'rlisum Vrer combining theltwq orrif recents. ,represented brA the rotation olf their@ shaftsllpand 8,!into a vector is of the conventional typeht; consists of two T-shaped members 3| and 3 \2, each with a slot, 3,3 andSd, in their respective legs and with racks, 35 and 36, on the *"aica outer surface of their respective cross arms. Racks 35 and 36 are adapted to engage gear wheels 31 and 38 connected to shafts and 8 respectively.` The legs of the members 3| and 32 are connected together by a pin 39 slidably securedin slots 33 and 34. The members 3| and 32 are restrained to move in the direction of their respective racks by guides (not shown). The legs of the members 3| and 32 and the slots 33 and 34 therein are of such lengths as will permit the rotation of shaft to move member 3| ten units to the right or left from its mean position upon ten Operation (Fig. 1)

Starting with all of the parts of the apparatus shown in Figure 1 in their mean positions, and

. assuming the direction of the arrows indicates rotations of increasing values, it will be seen that if differentials I5 and 23 were disconnected from shafts and 8, then ten units of movement of shafts I'and 8 each would move the pin 39 to the upper right-hand corner of the field 46, shown in dotted lines 4|. Likewise, pin 39 would be moved into the other corners, similarly shownin dotted l lines, upon the reversal of the direction of rotation of shaft or 8 or both. The limit .of travel into these areas would be controlled by the stops 3,3 and I0, I6 only.

VViththe differentials l5 and 23, and their asso- '.j ciated mechanisms, connected to shafts and 8,

stops I8 and I9 and stops 26 and 21 come into operative position when the sum ofthe movements of the components equals the value of 14.14 units, or the difference of the movements of the components equals the value of 14.14 units.

For example: If slide 4 only is moved 10 units to the right, pin 39 will be moved to position 42, when stop 5 engages stop 3vpreventing further rotation of shaft vIn this position theslides 28 and 28 have each moved 10 units to the right and shaft 8 is free to move either in a negative or a positive direction until the combined movement applied to slides 20 or 28 equals the value of 14.14 units when stop I9 engages stop I8 or stop 21 engages stop 26, according tothe direction'of rotation of shaft 8. This condition is illustrated in the drawing for a positive motion of shaft 8 of 4.14 units when pin 39 will have moved to point 43 and stop 21 will engage stop 26. It will now be seen that in order for the pin 39 to move to a position corresponding to a higher value of the Y component the X component must be correspondingly reduced.A 1n order for the Y component to be' increased to 10 units of movement the X component must be reduced to 4.14 units. The ratio of 4.14 units to the original 10 units selected is `equal to .414 or the tangent of 221/2. It will thus be'seen that the area towhich the pin 39 is limited inits travel is an Octagon.

Figure 2 discloses a mechanism equivalent in Vfunction to the two differentials and the additive and subtractive stop mechanism. The X component is represented by therotation of shaft 44, which has a threaded portion 45 adapted to move gear 46 vertically when it is kept from rotational movement. Stops 41, 41 are adapted to contact A stops 48, 48 upon the movement of gear 46 :a distance of 14.14 units from its mean position. `Shaft 44 is connected to shaft 49 by gears 58 and 5| and reproduces in shaft 49 its identical motion, but oppositein direction. On shaft 49 is a threaded portion 52 on which is mounted gear 53 adapted to move therealong upon rotation of shaft 49 and upon its being kept from rotation. Stops 54, 54 on gear 53 are adapted to engage stops 55, 55 upon the vertical movement of gear 53 a distance of 14.14 units from its mean position.

The Y component is represented by the movement of shaft 56 connected to gear 51 which is adapted to mesh with gears 46 and 53 throughout their vertical movements along their respective shafts.

Shaft 44 corresponds to shaft I of Fig. 1 and shaft 56 corresponds to shaft 8. In addition to y the compoundstop just described, the simple stops on the motors Mx and My are required as in Fig. 1. l'

A l Operation (Fig. 2))

Assuming all parts of the apparatus in their mean positions and that the direction of rotation of the shafts 44 and 56 for increasingvalues is shown bythe direction 'of the arrows thereon, it will be seen that with shaft 56 stationary and upon rotation of shaft 44 ten units from its mean position in a positive direction, gear 46 is moved down 10 units and gear l53 is moved up 10 units. With the Mx; unit against its simple stop, as

shown in Figure 1, no further movement Vof shaft 44 in la positive direction ispossible.

Upon the movement of vshaft 56 in a positive direction, with shaft 44 stationary, gear. 51rotates gear 46 on the threaded portion45 of shaft.` 44 and is moved down. It will be noted that` gear 46 can be moved down but 4.14 units until stop 41 engages stop 48, when'further rotation of shaft 56 is prevented. 1 l

Likewise a negative movement of shaft 456 will move gear 53 upward until it-has moved"4'.14 units, when stop 54 engages stop 55 and prevents further movement of shaft 56.l

The operation of the mechanism for Vnegative movements is apparent. Y v

It is of course understood that various changes may be made by those skilled in the art in the details of the embodiment of the invention illustrated in the vdrawing and described in detail above within the principle and scope of the invention as expressed in thev appended claims. For example, the elements, the movementsgof which it isdesired to stophave been shown as slides receiving their motion in proportion to the rotation of shafts. Ihe elements may be rotatinggears or cams receiving their motion in proportion to the linear movements ofV shafts. of combined movement ofthe components has been shown as an Octagon, which is similar in generalshape to a circle. The iieldnof movement may be made an oval or other figure by predetermining the ratio of the limits 0f movement of the output of the Ydifferentials to the limits of movement of the element that represents a movement of an indivi-dual component. 'v

1. A stop mechanism for two slides whose movements are generated by theV rotationof two individual shafts connected respectively thereto and including stops effective on saidlslides land said shafts, a plurality of meansconnected-between the said shafts the resultant 'movements of which means areV in proportion 'respectively to the *additive and the subtractive combination of the movements of said shafts, and stops on said means adapted to limit their movement. i

2. A stop mechanism for two slides whose Likewise, the field movements jfrcnn their meany positions are igen- .ratedby the `rotation of `tvvo individual rshafts connected,respectively thereto and including stopsjeifective on saidslides and said'shafts, a plurality of `means connected between the said shafts the resultant movements of which are in proportion respectively to the additive'and the sub- "tiactive movements of said slidesfrom their mean positions, and .stops on 'said'means `adapted to limit the combined movement 'of they slides from their mean positions in proportion to the maximum individual movement of the slidesfrom their man positions in the ratio of 14.14 to 10.

3. A stop mechanism for two slides whose movements from their mean positions are generated by the rotation of two individual shafts connected respectively thereto, stops on said slides, stops on said shafts adapted to become operative with the stops on said slides, a differential connected to said shafts the output of which is the sum of the movements of said shafts, stops associated with the said output, a second differential connected to said shafts the output of which is the difference in movements of said shafts, stops associated with the output of said second differential, the said stops associated with the said outputs being adapted to become operative when the -combined movements of said individual outputs have reached definite values.

4. A stop mechanism for two slides Whose movements from their mean positions are generated by the rotation of two individual shafts connected respectively thereto, stops on said slides, stops on said shafts adapted to become operative when the stops on said slides reach a position ten units of movement from their mean positions, a differential connected to said shafts the output of which is the sum of the movements of said shafts, stops associated with the said output, a second differential connected to said shafts the output of which is the difference in movements of said shafts, stops associated with the output of said second differential, the said stops associated with the said outputs being adapted to become operative when the combined movements of said individual outputs have reached 14.14 units of movement from their mean positions.

5. A stop mechanism for two slides whose movements are generated by the rotation of two individual shafts connected respectively thereto, stops on said shafts adapted to become operative when the said shafts have rotated ten units fromy their mean position, a differential connected to said shafts `the output of which is the sum of the movements of said shafts, stops associated with the said output, a second differential connected to the said shafts the output of which is the sum of the movements of said shafts but with the motion of one of said shafts applied to the second differential in a direction opposite to the direction of application to the first differential, stops associated with the outputI of said second differential, the said stops associated with the said outputs being adapted to become operative when the combined movements of said outputs have reached 14.14 units of movement from their mean positions.

6. A stop mechanism for two slides who'se movements are generated by the rotation of two individual shafts connected respectively thereto, stops effective on said slides, a threaded portion cn one of said shafts, a movable gear threaded on said shaft, a third shaft including a threaded portion, gears connecting the said third shaft to 'said one iofsads'hafts and adapted to rotate the lsaid thirdshaft in direct proportion but in a direction opposite to said one of said'shafts, a movablegearthreaded on said third shaft, an elongated gearvsecured to the second of said two 'shafts l"adapted to mesh with both of the said movable gears, and stops on said movable gears andsaid one of said shafts and said third shaft adapted to limitthe movement of said movable gears.` a

'7; A stop mechanism for twoslides whose indvementsvareI generated by the rotation of `two individual shaftsconnected respectively thereto, stops effective on said slides adapted to become operative when the said shafts have rotated ten units from their mean positions, a threaded portion on one of said shafts, a movable gear threaded on said threaded portion, a third shaft including a threaded portion, gears connecting said third shaft to said one of said shafts and adapted to rotate said third shaft in proportion and in a direction opposite to the direction of said one of said shafts, a movable gear threaded cn said third shaft, an elongated gear secured to the second of said two shafts adapted to mesh with both of the said movable gears, and stops on said movable gears and said one of said shafts and the said third shaft adapted to limit the movement of said movable gears when they have moved 14.14 units from their mean positions.

8. A stop mechanism for twoelements whose movements are generated by the movements of two individual shafts connected respectively thereto and including stops effective on said elements and said shafts, a plurality of means conerated by the movements of two individual shafts connectedV respectively thereto and including stops effective on said elements and said shafts, a plurality of means connected between the said shafts the resultant movements of which are in proportion respectively to the additive and theI subtractive movements of said elements from their mean positions, and stops on said means adapted to limit the comb-ined movement of the elements from their mean positions in proportion to the maximum individual movement of the elements from their mean positions in a predetermined ratio.

10. A stop mechanism for two slides whose movements are generated by the rotation of two individual shafts connected respectively thereto, stops on said shafts adapted to become operative when the said shafts have rotated a predetermined number of units from their mean position, a dierential connected to said shafts the output of which is the sum of the movements of said shafts, stops associated with the said output,

`a second differential connected to the said shafts associated with the said outputs being adapted to become operative when the combined movements of said outputs have reached a predeterminednumber of units of movement from their mean positions.

, 11. A stop mechanism for tWo elements whose movementsare generated by the rotation of two individual shafts connected respectively thereto, stops effective on said elements adapted to become operative when the said shafts have rotated shaftto said one of said shafts and adapted to rotate said third shaft in proportion and in a direction oppositevto the direction of said one of said shafts, a movable gear threaded on said third shaft, an elongated gear secured to the second of said two shafts adapted to mesh with both of the said movable gears, and stops on said movable gears and said one of said shafts and the said third shaft adapted to limit the movement of saidmovable gears when they have moved a predetermined number of units from their mean positions.

JAMES D. TEAR. 

